Federal charges filed in attack on U.S. mission in Benghazi

A vehicle is engulfed in flames inside the U.S. diplomatic compound in Benghazi late on Sept. 11, 2012.

A vehicle is engulfed in flames inside the U.S. diplomatic compound in Benghazi late on Sept. 11, 2012. (AFP/ Getty Images)

Richard A. Serrano and Ken Dilanian

WASHINGTON -- Federal criminal charges have been filed against one or more assailants in the attacks on the U.S. mission in Benghazi, Libya, two law enforcement sources said Tuesday.

They declined to discuss details because the case is filed under seal and the investigation is continuing.

One of the law enforcement officials said Ahmed Abu Khattala, a top Libyan militia commander, had been charged in the attack, which resulted in the death of the U.S. ambassador to Libya, J. Christopher Stevens, and three other Americans in September.

For months, the Obama administration has been under increasing pressure, primarily from Republicans, to ensure that someone be held accountable for the raid and burning of the mission. Allegations have been made that the Department of Justice and FBI have not made a concerted effort to make arrests.

Much of the mission compound was looted and trampled, making the crime scene difficult to analyze. FBI Director Robert S. Mueller III told the House Judiciary Committee in June that U.S. agents could not immediately get into the area because of safety concerns.

Mueller said a two-week delay in getting access to the site “adversely impacted the ability to gather evidence in a variety of ways and adversely impacted the investigation."

"In Benghazi, there is no law enforcement," he explained. "There is nobody that you can deal with in terms of assuring your security."

In addition, putting agents into the country was dependent on getting visas from the Libyan government and "the government then and today is still unstable," Mueller said. "It's very difficult to get any decision made."